Improvement of thermoelectric performance of tetrahedrite Cu12Sb4S13 by energy band regulation and point defect engineering
A series of Cui12-xGaxSb4S13(x=0,0.05,0.1 and 0.15)samples were synthesized through high-tem-perature melting method and heat annealing technique combined with spark plasma sintering(SPS).The phase composition,band structure and thermoelectric properties of the samples were characterized and analyzed.The results show that Ga doping can introduce impurity band near the conduction band,acting as donor energy lev-el,thus reducing the hole carrier concentration and increasing the Seebeck coefficient of the samples.At the same time,with the increase of Ga doping content,the thermal conductivity of Ga-doped samples decreases sig-nificantly.When the temperature is 770 K,the thermal conductivity of Cu11.85Ga0.15Sb4S13 sample decreases to 1.20 W/mK,which is 29％lower than that of the intrinsic material.Finally,the maximum ZT value of 0.7 is a-chieved for Cu11.9Ga0.1Sb4S13 sample at 770 K,a 40％improvement over the intrinsic Cu12Sb4S13.
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